<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
</head>
<body>

</body>
</html>
<script>
    function fun1() {
        console.log(a)
    }
    function fun2() {
        var a = 11;
        fun1();

    }
    fun2()
</script>